Symbiotic optical solitons and modulational instability

Abstract

The interaction due to cross phase modulation of dark and bright solitons propagating in optical fibers is studied analytically, within the frame workof a variational approach as well as numerically. It is demonstrated that theinteraction of a bright soliton in the anomalous dispersion regime with adark soliton in the normal dispersion regime is described by a repulsiveeffective potential. In the reverse case when a bright soliton in the normaldispersion regime intracts with a dark soliton in the anomalous dispersionregime, the dark and bright solitons may form a symbiotic soliton, which isstable with respect to small mismatches in group velocity and initial relativeposition of the separate solitons. The influence of the symbiotic soliton onthe modulational instability of the carrier c.w. background is also analysed.Analytical results are in good agreement with numerical simulations. Show more